Merge pull request #42 from ethul/topic/stderr

Writes PureScript output to stderr

5 files changed, 40 insertions, 19 deletions

diff --git a/bower.json b/bower.json
index 761c24c..681612d 100644
--- a/bower.json
+++ b/bower.json
@@ -5,6 +5,7 @@
     "purescript-aff": "^0.13.0",
     "purescript-foreign": "^0.7.0",
     "purescript-unsafe-coerce": "~0.1.0",
-    "purescript-nullable": "~0.2.1"
+    "purescript-nullable": "~0.2.1",
+    "purescript-node-process": "~0.4.1"
   }
 }
diff --git a/docs/PursLoader/Loader.md b/docs/PursLoader/Loader.md
index bb02470..d05e3b7 100644
--- a/docs/PursLoader/Loader.md
+++ b/docs/PursLoader/Loader.md
@@ -3,19 +3,25 @@
 #### `Effects`
 
 ``` purescript
-type Effects eff = (loader :: Loader | eff)
+type Effects eff = (console :: CONSOLE, err :: EXCEPTION | eff)
+```
+
+#### `Effects_`
+
+``` purescript
+type Effects_ eff = Effects (loader :: Loader | eff)
 ```
 
 #### `loader`
 
 ``` purescript
-loader :: forall eff. LoaderRef -> String -> Eff (Effects eff) Unit
+loader :: forall eff. LoaderRef -> String -> Eff (Effects_ eff) Unit
 ```
 
 #### `loaderFn`
 
 ``` purescript
-loaderFn :: forall eff. Fn2 LoaderRef String (Eff (Effects eff) Unit)
+loaderFn :: forall eff. Fn2 LoaderRef String (Eff (Effects_ eff) Unit)
 ```
 
 
diff --git a/docs/PursLoader/Plugin.md b/docs/PursLoader/Plugin.md
index 7a524da..9f9f852 100644
--- a/docs/PursLoader/Plugin.md
+++ b/docs/PursLoader/Plugin.md
@@ -3,7 +3,7 @@
 #### `Compile`
 
 ``` purescript
-type Compile eff = Nullable Error -> DependencyGraph -> Eff eff Unit
+type Compile eff = Nullable Error -> DependencyGraph -> String -> Eff eff Unit
 ```
 
 #### `Context`
diff --git a/src/PursLoader/Loader.purs b/src/PursLoader/Loader.purs
index 402e805..c50c63c 100644
--- a/src/PursLoader/Loader.purs
+++ b/src/PursLoader/Loader.purs
@@ -1,23 +1,28 @@
 module PursLoader.Loader
   ( Effects()
+  , Effects_()
   , loader
   , loaderFn
   ) where
 
-import Prelude (Unit(), ($), (>>=), (<$>), (<*>), (++), (<<<), bind, const, id, pure, unit)
+import Prelude (Unit(), ($), (>>=), (<$>), (<*>), (++), (<<<), bind, const, id, pure, unit, void)
 
-import Control.Alt ((<|>))
 import Control.Bind (join)
 import Control.Monad.Eff (Eff(), foreachE)
-import Control.Monad.Eff.Exception (Error(), error)
+import Control.Monad.Eff.Console (CONSOLE())
+import Control.Monad.Eff.Exception (EXCEPTION(), Error(), error, message)
 
 import Data.Array ((!!))
 import Data.Either (Either(..), either)
 import Data.Function (Fn2(), mkFn2)
-import Data.Maybe (Maybe(..), maybe)
+import Data.Maybe (maybe)
 import Data.Nullable (toMaybe)
 import Data.String.Regex (Regex(), match, noFlags, regex)
 
+import Node.Encoding (Encoding(UTF8))
+import Node.Process (stderr)
+import Node.Stream (writeString)
+
 import Unsafe.Coerce (unsafeCoerce)
 
 import PursLoader.LoaderRef
@@ -34,9 +39,11 @@ import PursLoader.Debug (debug)
 import PursLoader.Path (dirname, joinPath, relative)
 import PursLoader.Plugin as Plugin
 
-type Effects eff = (loader :: Loader | eff)
+type Effects eff = (console :: CONSOLE, err :: EXCEPTION | eff)
+
+type Effects_ eff = Effects (loader :: Loader | eff)
 
-loader :: forall eff. LoaderRef -> String -> Eff (Effects eff) Unit
+loader :: forall eff. LoaderRef -> String -> Eff (Effects_ eff) Unit
 loader ref source = do
   callback <- async ref
 
@@ -46,25 +53,32 @@ loader ref source = do
 
   pluginContext.compile (compile callback)
   where
-  pluginContext :: Plugin.Context (Effects eff)
+  pluginContext :: Plugin.Context (Effects_ eff)
   pluginContext = (unsafeCoerce ref).purescriptWebpackPluginContext
 
-  compile :: AsyncCallback eff -> Plugin.Compile (Effects eff)
-  compile callback error' graph = do
+  compile :: AsyncCallback (Effects eff) -> Plugin.Compile (Effects_ eff)
+  compile callback error' graph output = do
     either (const $ pure unit) (\a -> debug ("Adding PureScript dependency " ++ a)) name
 
     addDependency ref (resourcePath ref)
 
-    either (\err -> callback (toMaybe error' <|> Just err) "") id
+    void $ writeString stderr UTF8 output (pure unit)
+
+    maybe (pure unit) (\a -> void $ writeString stderr UTF8 (message a) (pure unit)) (toMaybe error')
+
+    either (const $ callback (pure fixedError) "") id
            (handle <$> name <*> dependencies <*> exports)
     where
-    handle :: String -> Array String -> String -> Eff (Effects eff) Unit
+    fixedError :: Error
+    fixedError = error "PureScript compilation has failed."
+
+    handle :: String -> Array String -> String -> Eff (Effects_ eff) Unit
     handle name' deps res = do
       debug ("Adding PureScript dependencies for " ++ name')
       foreachE deps (addDependency ref)
       debug "Generated loader result"
       debug res
-      callback (toMaybe error') res
+      callback (const fixedError <$> toMaybe error') res
 
     exports :: Either Error String
     exports =
@@ -98,5 +112,5 @@ loader ref source = do
       re :: Regex
       re = regex "(?:^|\\n)module\\s+([\\w\\.]+)" noFlags { ignoreCase = true }
 
-loaderFn :: forall eff. Fn2 LoaderRef String (Eff (Effects eff) Unit)
+loaderFn :: forall eff. Fn2 LoaderRef String (Eff (Effects_ eff) Unit)
 loaderFn = mkFn2 loader
diff --git a/src/PursLoader/Plugin.purs b/src/PursLoader/Plugin.purs
index c798c83..8bb53be 100644
--- a/src/PursLoader/Plugin.purs
+++ b/src/PursLoader/Plugin.purs
@@ -15,7 +15,7 @@ import Data.Either (Either(..))
 import Data.Function (Fn4(), runFn4)
 import Data.Nullable (Nullable())
 
-type Compile eff = Nullable Error -> DependencyGraph -> Eff eff Unit
+type Compile eff = Nullable Error -> DependencyGraph -> String -> Eff eff Unit
 
 type Context eff = { compile :: Compile eff -> Eff eff Unit, options :: Options }